Generally, an aerial ladder truck is used for rescuing people or extinguishing fire in the event of a fire in a multistory building, or lifting up or taking down articles such as stuff packed for moving in an apartment or building, wherein a person rides in a bucket that moves along a multistage boom to rescue people or extinguish fire, and also to load and carry stuff in the bucket.
One example of a conventional aerial ladder truck is disclosed in Korean Patent No. 1251991, titled “AERIAL LADDER TRUCK” (hereinafter referred to as the “conventional aerial ladder truck”).
The conventional aerial ladder truck includes a vehicle; a base frame mounted on the vehicle; a plurality of outriggers mounted on left and right sides at the front and rear of the base frame and telescopically extensible in multiple stages; a ladder apparatus mounted at the top of the base frame and provided with an extensible ladder; and a bucket mounted on the extensible ladder to move therealong.
The ladder apparatus includes a fixed ladder, one end of which is rotatably coupled to the base frame by means of a hinge shaft; an extensible ladder comprising a multi-stage ladder inserted inside the fixed ladder and slidably moving in multiple stages; and an angle adjusting cylinder for pivoting the fixed ladder upwardly and downwardly about the hinge shaft at a predetermined angle with respect to the base frame.
While the angle of the extensible ladder may be adjusted upwardly and downwardly as described above, the extensible ladder is also mounted at the top of a turntable mounted to pivot in a horizontal direction. That is, one end of the extensible ladder is connected at the top of the turntable by means of the hinge shaft, so that the angle thereof may be adjusted.
However, the conventional aerial ladder truck configured as above has the following problems.
First, the conventional aerial ladder truck has a problem in that no articles can be loaded in a space below the extensible ladder and above the base frame because the extensible ladder is inclined as one end thereof is fixed to the turntable by means of the hinge shaft.
Further, the conventional ladder truck has another problem in that the height of the truck may be restricted by a bridge, a pedestrian overpass or the like while driving the truck because the extensible ladder is inclined as one end thereof is fixed to the turntable by means of the hinge shaft, so that the height of the other end thereof is increased.
Furthermore, the conventional aerial ladder truck has yet another problem in that the extensible ladder may frequently fall down due to the weight of articles or a gust from outside or the like while carrying the articles because the extensible ladder is inclined as one end thereof is fixed to the turntable by means of the hinge shaft, so that the inclination thereof is increased while it is telescopically extended to carry the articles.